Buggy code:
public class CSVFormat implements Serializable { private static final long serialVersionUID = 1L ; private final Character delimiter ; private final Character encapsulator ; private final Character commentStart ; private final Character escape ; private final boolean ignoreSurroundingSpaces ; private final boolean ignoreEmptyLines ; private final String lineSeparator ; private final String [ ] header ; static final CSVFormat PRISTINE = new CSVFormat ( null , null , null , null , false , false , null , null ) ; public static final CSVFormat DEFAULT = CSVFormat . PRISTINE . withDelimiter ( Constants . COMMA ) . withEncapsulator ( Constants . DOUBLE_QUOTE ) . withIgnoreEmptyLines ( true ) . withLineSeparator ( Constants . CRLF ) ; public static final CSVFormat RFC4180 = CSVFormat . PRISTINE . withDelimiter ( Constants . COMMA ) . withEncapsulator ( Constants . DOUBLE_QUOTE ) . withLineSeparator ( Constants . CRLF ) ; public static final CSVFormat EXCEL = CSVFormat . PRISTINE . withDelimiter ( Constants . COMMA ) . withEncapsulator ( Constants . DOUBLE_QUOTE ) . withLineSeparator ( Constants . CRLF ) ; public static final CSVFormat TDF = CSVFormat . PRISTINE . withDelimiter ( Constants . TAB ) . withEncapsulator ( Constants . DOUBLE_QUOTE ) . withIgnoreSurroundingSpaces ( true ) . withIgnoreEmptyLines ( true ) . withLineSeparator ( Constants . CRLF ) ; public static final CSVFormat MYSQL = CSVFormat . PRISTINE . withDelimiter ( Constants . TAB ) . withEscape ( Constants . ESCAPE ) . withLineSeparator ( Constants . LF ) ; public CSVFormat ( final Character delimiter , final Character encapsulator , final Character commentStart , final Character escape , final boolean surroundingSpacesIgnored , final boolean emptyLinesIgnored , final String lineSeparator , final String [ ] header ) { } private static boolean isLineBreak ( final Character c ) { } void validate ( ) throws IllegalStateException { if ( ( delimiter ) == ( encapsulator ) ) { <START_BUG> throw new IllegalStateException ( ( ( "The<seq2seq4repair_space>encapsulator<seq2seq4repair_space>character<seq2seq4repair_space>and<seq2seq4repair_space>the<seq2seq4repair_space>delimiter<seq2seq4repair_space>cannot<seq2seq4repair_space>be<seq2seq4repair_space>the<seq2seq4repair_space>same<seq2seq4repair_space>('" + ( encapsulator ) ) + ")" ) ) ; <END_BUG> } if ( ( delimiter ) == ( escape ) ) { throw new IllegalStateException ( ( ( "The<seq2seq4repair_space>escape<seq2seq4repair_space>character<seq2seq4repair_space>and<seq2seq4repair_space>the<seq2seq4repair_space>delimiter<seq2seq4repair_space>cannot<seq2seq4repair_space>be<seq2seq4repair_space>the<seq2seq4repair_space>same<seq2seq4repair_space>('" + ( escape ) ) + "')" ) ) ; } if ( ( delimiter ) == ( commentStart ) ) { throw new IllegalStateException ( ( ( "The<seq2seq4repair_space>comment<seq2seq4repair_space>start<seq2seq4repair_space>character<seq2seq4repair_space>and<seq2seq4repair_space>the<seq2seq4repair_space>delimiter<seq2seq4repair_space>cannot<seq2seq4repair_space>be<seq2seq4repair_space>the<seq2seq4repair_space>same<seq2seq4repair_space>('" + ( commentStart ) ) + "')" ) ) ; } if ( ( ( encapsulator ) != null ) && ( ( encapsulator ) == ( commentStart ) ) ) { throw new IllegalStateException ( ( ( "The<seq2seq4repair_space>comment<seq2seq4repair_space>start<seq2seq4repair_space>character<seq2seq4repair_space>and<seq2seq4repair_space>the<seq2seq4repair_space>encapsulator<seq2seq4repair_space>cannot<seq2seq4repair_space>be<seq2seq4repair_space>the<seq2seq4repair_space>same<seq2seq4repair_space>('" + ( commentStart ) ) + "')" ) ) ; } if ( ( ( escape ) != null ) && ( ( escape ) == ( commentStart ) ) ) { throw new IllegalStateException ( ( ( "The<seq2seq4repair_space>comment<seq2seq4repair_space>start<seq2seq4repair_space>and<seq2seq4repair_space>the<seq2seq4repair_space>escape<seq2seq4repair_space>character<seq2seq4repair_space>cannot<seq2seq4repair_space>be<seq2seq4repair_space>the<seq2seq4repair_space>same<seq2seq4repair_space>('" + ( commentStart ) ) + "')" ) ) ; } } public char getDelimiter ( ) { } public CSVFormat withDelimiter ( final char delimiter ) { } public CSVFormat withDelimiter ( final Character delimiter ) { } public Character getEncapsulator ( ) { } public CSVFormat withEncapsulator ( final char encapsulator ) { } public CSVFormat withEncapsulator ( final Character encapsulator ) { } public boolean isEncapsulating ( ) { } public Character getCommentStart ( ) { } public CSVFormat withCommentStart ( final char commentStart ) { } public CSVFormat withCommentStart ( final Character commentStart ) { } public boolean isCommentingEnabled ( ) { } public Character getEscape ( ) { } public CSVFormat withEscape ( final char escape ) { } public CSVFormat withEscape ( final Character escape ) { } public boolean isEscaping ( ) { } public boolean getIgnoreSurroundingSpaces ( ) { } public CSVFormat withIgnoreSurroundingSpaces ( final boolean ignoreSurroundingSpaces ) { } public boolean getIgnoreEmptyLines ( ) { } public CSVFormat withIgnoreEmptyLines ( final boolean ignoreEmptyLines ) { } public String getLineSeparator ( ) { } public CSVFormat withLineSeparator ( final char lineSeparator ) { } public CSVFormat withLineSeparator ( final String lineSeparator ) { } String [ ] getHeader ( ) { } public CSVFormat withHeader ( final String ... header ) { } public Iterable < CSVRecord > parse ( final Reader in ) throws IOException { } public String format ( final String ... values ) { } @ Override public String toString ( ) { } }

Fix:
throw new IllegalStateException ( ( ( "The<seq2seq4repair_space>encapsulator<seq2seq4repair_space>character<seq2seq4repair_space>and<seq2seq4repair_space>the<seq2seq4repair_space>delimiter<seq2seq4repair_space>cannot<seq2seq4repair_space>be<seq2seq4repair_space>the<seq2seq4repair_space>same<seq2seq4repair_space>('" + ( encapsulator ) ) + "')" ) ) ;